Vertically loaded heat treating oven



Feb. 21, 1967 J. M. BEYVL 3,305,225

VERTICALLY LOADED HEAT TREATING OVEN Filed March 5, 1964 2 Sheets-Sheet l 22 I9 lull SJ:

INVENTOR. JOSEPH/M BEYVL 'Feb. 21, 1967 J. M. BEYVL 3,305,225

VERTICALLY LOADED HEAT TREATING OVEN Filed Marofi 5, 1964 2 Sheets-Sheet 2 INVENTOR.

(/OSEPH /I/[. 5133/ VL United States Patent Ofifice 3,3d5,225 Patented Feb. 21, 1967 3,305,225 VERTICALLY LOADED HEAT TREATING OVEN Joseph M. Beyvl, Cleveland Heights, Ohio, assignor, by mesne assignments, to Bangor Punta Operations, Inc., Bangor, Maine, a corporation of New York Filed Mar. 5, 1964, Ser. No. 349,605 Claims. ((31. 26336) The present invention relates as indicated to a vertically loaded heat treating oven and more particularly to an improved oven construction for more efficiently heat treating articles placed therein. It will be understood that the term oven as used herein is employed in a broad sense, and is intended to include both relatively low and relatively high temperature heat treating enclosures. In other words, the term oven employed herein is meant to include both ovens and furnaces.

In present heat treating ovens, it is common practice to suspend or otherwise temporarily position the articles to be heat treated in the oven directly exposed to circulating fluid which contacts the surfaces of the articles for achieving the heat treatment. The circulating fluid in the present invention comprises the heated air within the oven, although it will be apparent that other gaseous media could be satisfactorily employed, with the desired heat treatment being effected through intimate contact of the circulating air with the surface of the articles. In present such ovens generally the heated air is circulated through the entire oven interior with the result that the velocity of the air and thus the rate of heat transfer is relatively limited due to the relatively large volume through which the air circulates.

An object of the present invention is to provide a heat treating oven which eflects an increased rate of heat transfer to the articles placed therein.

A more specific object of the invention is to provide such an oven wherein the interior thereof is constructed and arranged to provide particular confined paths of air flow around the articles placed therein thereby to increase the velocity of the air and the rate of heat transfer to such articles.

A further aspect of the present invention is the provision of means in the confined path of air flow to produce turbulence thereby further enhancing the heat transfer to the articles.

These and other objects and advantages of the present invention will become apparent as the following description proceeds.

To the accomplishment of the foregoing and related ends, the invention, then, comprises the features hereinafter fully described and particularly pointed out in the claims, the following description and the annexed drawings setting forth in detail certain illustrative embodiments of the invention, these being indicative, however, of but a few of the various ways in which the principle of the invention may be employed.

In said annexed drawings:

FIG. 1 is a sectional view taken on line 11 of FIG. 2;

FIG. 2 is a vertical cross sectional view taken on line 2-2 of FIG. 1;

FIG. 3 is a slightly enlarged sectional view taken on line 33 of FIG. 2; and

FIG. 4 illustrates a modified form of article-enveloping sleeve.

Referring now to the drawings in detail, wherein like parts are designated by like reference numerals, the heat treating oven of the present invention is generally indicated at and is of the top loading type, being provided with a plurality of upwardly extending, generally rectangular top sections 11 which form openings 12 in the top of the oven for loading and unloading articles from the oven interior for heat treatment. A cover 13 is provided for each opening 12, the covers being hinged or otherwise movable to and from a position closing the respective openings by any suitable means, such as fluid cylinder means, an overhead crane or like equipment, an apertured lug portion 14 being provided with each cover to adapt the same for lifting. In a conventional manner, the covers 13 are provided with bottom flanged portions 15 adapted to extend downwardly into sand-containing channel members 16 secured to the top of the oven for sand sealing the covers in a closed position. Although four openings and associated covers are illustrated, it will be apparent that more or less could as well be provided. The oven walls and the covers are provided in the usual manner with insulated lining portions for heat retention purposes.

A platform 17 is mounted at one side of the oven 10 and supports a pair of fan motors 18 and 19 which drive recirculating fans 20 and 21, respectively, mounted within the oven enclosure for circulating the air through the oven. A ladder 22 is provided at one end of the platform 17 for access thereto.

A burner 23 of conventional construction is mounted in the side wall 24 of the oven above the recirculating fans and produces an inwardly directed flame jet through which the recirculated air passes for heating the same. A protective plate 25 is provided directly in front of and spaced from the burner for shielding the vertical wall behind the plate.

Mounted outwardly of the oven at the opposite side 26 thereof is an exhaust fan 27 supported on a supporting platform 28. The inlet of the exhaust fan 27 is connected to an upwardly extending exhaust duct 29 the opposite end of which is mounted in an opening 30 in the oven side wall 26. The exhaust fan functions to purge the oven interior of combustible gases before the heat treating operation and is operated during the heat treating operation to reduce the amount of products of combustion. An access door 31 is mounted in the side wall 26 for permitting access to the oven interior for inspection, maintenance, or the like.

An insulated transverse vertical wall 32 extends across the oven interior dividing the same into heating equipment and heat treating compartments as shown, wall 32 terminating substantially above the oven floor 33 and below the oven top, referring to FIG. 2. The air is drawn over the top of the wall 32 as indicated by the arrows, with the outlets of the recirculating fans directing the air beneath the bottom of the wall 32 as indicated. A similarly transversely extending horizontal divider member 34 extends from the wall 32 to the side wall 24, with openings being provided in the divider for receiving the recirculating fans 20 and 21.

Disposed between the wall 32 and the oven side wall 26 and extending between the adjacent, oppositely extending side walls 35 and 36 are upper and lower partitions 37 and 38, respectively. Each of the partitions 37 and 38 is secured to the adjacent side walls by any suitable support means (not illustrated) and in such a manner to eliminate air gaps therebetween. Each of the partitions 37 and 38 is provided with openings commonly designated at 39 which are, when the partitions are mounted in place, vertically aligned to receive cylindrical shells or casings commonly designated at 40. The shells 40 are secured to the partitions 37 and 38 by any suitable means and are open at their tops and bottoms to admit air therethrough as indicated by the arrows. In the form shown there are four openings provided in both the top and bottom partitions 37 and 38, respectively, and four cylindrical shells 40 are disposed between the partitions within the openings, with each cylindrical shell being disposed generally below the respective opening 12 in the oven top. It will thus be seen that the bottom partition 3S and divider 34 form with the oven floor 33 a plenum chamber 41, and that the upper partition 37 forms with the top of the oven a plenum chamber 42 of irregular configuration. It will further be seen that air directed to plenum chamber 41 must flow upwardly through the shells 40.

A series of fluid deflectors 43 are mounted on the oven floor generally below the cylindrical shells 40 for deflecting air impinging thereupon upwardly through the cylindrical shells 40. The number of such deflectors as will be apparent is not critical, with the deflectors associated With the front shells, that is, the shells nearest the recirculating fans and 21, being transversely staggered, referring to FIG. 3, relative to the deflectors associated with the back shells so as to provide relatively uniform fluid flow to all of the shells. A deflector 44 is mounted on the wall 32 adjacent the bottom thereof and extends downwardly into the plenum chamber 41 for directing the air generally toward the deflectors 43.

The articles to be heat treated are disposed within the cylindrical shells in spaced relation thereto to provide annular passages 45, thus exposing the entire peripheral surface of the articles to the air directed upwardly through the shells. The articles to be heat treated exemplified in the drawings comprise steel rolls R, with a single roll being disposed in each shell 40 in spaced relation thereto. The rolls R are of the type commonly used in steel roll mills and paper making machinery, the heat treating effecting a desired improvement in the surface hardness thereof.

Each of the rolls R is suspended within its associated shell 40 by means comprising a pair of supporting members commonly designated at 46 each of which is provided with a peripheral flange portion 47 which seats on the upwardly directed top sections 11 of the oven 10. The adjacent end of the shaft S of the roll R is connected to a lift attaching member 48 which extends upwardly between the supporting members 46. The attaching member 48 is provided with a transverse opening adapted to receive a pin 49 of suflicient length so as to overlie the supports 46 as clearly shown in FIG. 1 whereby the roll R can be suspended within the shell 40. The attaching member 48 is provided with an extension 50 for lifting the same by means of a crane or the like.

The manner in which the rolls R are heat treated should now be apparent. After the rolls R are suspended in place as above described, and the covers 13 sealed in a closed position, the exhaust fan 27 is preferably operated for a predetermined time period for purging the oven interior. The recirculating fans are then turned on and the burner 23 ignited whereby the air is circulated within the oven in the manner indicated by the arrows in FIG. 2. The air is thus directed from the fan outlets through the bottom plenum chamber 41 upwardly through the annular passages between the cylindrical shells 40 and the rolls R, with the deflectors 43 deflecting the air upwardly therethrough. After leaving the upper portions of the shells 40, the air is drawn in from the upper plenum chamber 42 by the fan inlets and redirected to the bottom plenum chamber 41.

By circulating the air through the relatively confined passages 45 between the rolls R and the shells 40, the air velocity is substantially increased, resulting in a corresponding increase in the rate of heat transfer to the rolls R. In fact, the heat treating oven of the present invention has a rate of heat transfer approximately double that of comparable size ovens in which the air is circulated through the entire oven interior. Thus, for a given size oven, approximately twice the number of articles can be treated in a given time period when compared with present ovens where the air circulation is unrestricted.

There is illustrated in FIG. 4 a modified form of shell, indicated by reference numeral 40', wherein the shell wall, instead of being smooth as in the previous described form, is provided with corrugations 51. Such corrugations create turbulence to the air flowing upwardly through the shell thereby to further enhance the contact with and heat transfer to the rolls R. Although generally horizontal corrugations have been shown in FIG. 4, it will be apparent that the corrugations may be helically formed to provide an upward swirl of the air, or different means such as deflectors or the like may be employed to produce the desired turbulence.

It will be apparent that the principles of the present invention can be varied by one skilled in the art without departing from the inventive concepts herein. For example, the structure which affords the improved heat transfer characteristics could be equally as well employed as a cooler. Thus, controlled temperature cooling air could be directed upwardly through the shells for cooling high temperature articles suspended or otherwise positioned therewithin, with the substantially increased rate of heat transfer afforded by means of the present invention substantially expediting the cooling process. Further, although in the form shown a single article is suspended within each shell, more than one article could be placed at one time in a single shell. Also, it should be apparent that solid articles of varying configurations and tubular articles as well could be treated in accordance with the present invention.

Other modes of applying the principle of the invention may be employed, change being made as regards the details described, provided the features stated in any of the following claims or the equivalent of such be employed.

I therefore particularly point out and distinctly claim as my invention:

1. A heat treating oven having openings in the top thereof through which articles can be placed in the oven interior for heat treatment therein, means for sealing said openings, burner means mounted on a wall of said oven and communicating with the oven interior for heating the same, fan means for circulating the air within said oven, upper partition means mounted in said oven below said openings and spaced from the top of the oven and forming therewith an upper plenum chamber, lower partition means mounted below said upper partition means and spaced from the oven bottom to form therewith a lower plenum chamber, a plurality of shell means mounted between said partitions, each of said shells being open at both ends which communicate respectively with the upper and lower plenum chambers, each of said shells receiving in spaced relation articles to be heat treated by the circulating heated air, the air circulated by said fan means being directed to said bottom plenum chamber and then upwardly through said shells in the spaces between the shells and the articles, the air directed upwardly through said shells increasing in velocity thereby increasing the rate of heat transfer to said articles.

2. An oven having an opening in the top thereof through which an article can be loaded and unloaded from the oven interior, cover means for sealing said opening, burner means for heating the oven interior, means for suspending the article in the oven, shell means mounted in said oven adapted to encircle the article in spaced relation to afford a relatively restricted passage through said shell around said article, fan means for circulating the air within the oven, and means for directing the circulated air upwardly through said passage between said shell and said article, the velocity of air increasing as it passes through said restricted passage, thereby increasing the rate of heat transfer to said article, said directing means including a bottom partition mounted in the oven above the bottom thereof having an opening for mounting the lower end of said shell, the partition being otherwise imperforate and form-ing with the oven bottom a lower plenum chamber through which air circulated by said fan means passes before flowing upwardly through said passage.

3. The combination of claim 2 wherein said directing means further includes deflector means extending into said lower plenum chamber for guiding air upwardly through said passage.

4. An oven having a plurality of openings in the top thereof through which articles can be loaded and unloaded from the oven interior, cover means for sealing each of said openings, burner means for heating the oven interior, means for suspending each of the articles in the oven, a plurality of shells mounted in the oven generally below said openings, each of said shells being adapted to receive an article in spaced relation to aflord a relatively restricted annular passage through said shell around said article, means for circulating the air within the oven, and means for directing the circulated air upwardly through each of said passages between the shells and said articles, the velocity of the air passing upwardly through said annular passage increasing thereby increasing the rate of heat transfer to said articles, said directing means including a bottom partition mounted in the oven above the bottom thereof 'having openings for mounting the lower ends of said shells, said bottom partition being otherwise imperforate and forming with the oven bottom a lower plenum chamber through which air circulated by said fan means passes before flowing upwardly through said passages.

5. The combination of claim 4 wherein said directing means further includes a plurality of deflector means extending into said lower plenum chamber below said shells for guiding air upwardly through said passages.

References Cited by the Examiner UNITED STATES PATENTS 1,844,604 2/1932 Schwab.

2,029,176 1/ 1936 Lindberg.

2,232,391 2/ 1941 Keller.

2,676,007 4/1954 Davis 263-40 X 2,805,054 9/1957 Hill 266-5 X FREDERICK L. MATTESON, JR., Primary Examiner.

20 JOHN J. CAMBY, Examiner. 

2. AN OVEN HAVING AN OPENING IN THE TOP THEREOF THROUGH WHICH AN ARTICLE CAN BE LOADED AND UNLOADED FROM THE OVEN INTERIOR, COVER MEANS FOR SEALING SAID OPENING, BURNER MEANS FOR HEATING THE OVEN INTERIOR, MEANS FOR SUSPENDING THE ARTICLE IN THE OVEN, SHELL MEANS MOUNTED IN SAID OVEN ADAPTED TO ENCIRCLE THE ARTICLE IN SPACED RELATION TO AFFORD A RELATIVELY RESTRICTED PASSAGE THROUGH SAID SHELL AROUND SAID ARTICLE, FAN MEANS FOR CIRCULATING THE AIR WITHIN THE OVEN, AND MEANS FOR DIRECTING THE CIRCULATED AIR UPWARDLY THROUGH SAID PASSAGE BETWEEN SAID SHELL AND SAID ARTICLE, THE VELOCITY OF AIR INCREASING AS IT PASSES THROUGH SAID RESTRICTED PASSAGE, THEREBY INCREASING THE RATE OF HEAT TRANSFER TO SAID ARTICLE, SAID DIRECTING MEANS INCLUDING A BOTTOM PARTITION MOUNTED IN THE OVEN ABOVE THE BOTTOM THEREOF HAVING AN OPENING FOR MOUNTING THE LOWER END OF SAID SHELL, THE PARTITION BEING OTHERWISE IMPERFORATE AND FORMING WITH THE OVEN BOTTOM A LOWER PLENUM CHAMBER THROUGH WHICH AIR CIRCULATED BY SAID FAN MEANS PASSES BEFORE FLOWING UPWARDLY THROUGH SAID PASSAGE. 